Variable speed transmission device



Nov. 14, 1939. D. HEYER VARIABLE SPEED TRANSMISSION DEVICE OriginalFiled Aug. 26, 1935 3 Sheets-Sheet 1 INVENTOR uQIiIezietL A TTORNEY Nov.14, 1939. D. HEYER VARIABLE-SPEED TRANSMISSION DEVICE Original FiledAug. 26, 1935 3 Sheets-Sheet 2 v INVENTOR. D nHe at" BY ATTORNEY. Y

Nov. 14, 1939. D. HEYER 2,179.933.

VARIABLE SPEED TRANSMISSION DEVICE Original Filed Aug. 26, 1955 3Sheets-Sheet I5 Patented ov. 14, 1939 SMISSION DEVICE Application August26, 1935, Serial No. 37,960

Renewed May 7, 1938 This invention relates to a source of variable speedpower for driving machines, which require a wide variation in drivingspeed, and more particularly to an integral construction incorporating adriving electric motor and a variablespeed ratio transmission fortransmitting power from the driving electric motor to a load drivingshaft.

In this invention the variation in speed is ob- 1c tained by means of abelt and pulley drive, in cluding a driving pulley structure, a drivenpulley structure, and a belt for transmitting power between the pulleystructures, at least one of the pulley structures having an adjustableeifective diameter, whereby the variation in speed ratio is obtained.

Such an adjustable pulley structure may include a pair of pulleysections having opposed inclined faces, forming a seat for awedge-shaped driving belt. In order to provide means for adjusting theeffective diameter of the pulley struc ture, the pulley sections aremade relative axially adjustable. In this way the inclined faces can bebrought closer together, causing the belt to be urged radially outwardto produce an increased efiective diameter; or they can be separated,

causing the belt to contact with the inclined faces at a shorter radialdistance to produce a decreased efiective diameter.

39 The variation in effective diameter and thus the variation in speedratio, which may be obtained by the use of such an adjustable pulleystructure, is determined by the practical width of the belt, the beltvelocity, and the maximum andminimum efiective diameters over which thebelt may be operated at the speed of rotation of the pulley structure.The minimum efiective diameter of the adjustable pulley structure isdetermined by the minimum diameter over which go the belt may beoperated at the peripheral velocity corresponding to the effectivepulleydiameter and the rate of rotation. For the belt will fail, if itis operated over too small a pulley diameter, due to the shearingstresses produced within the belt, when the belt is bent around thepulley. The maximum efiective diameter of the adjustable pulleystructure is determined by the thickness and width of the belt and theperipheral velocity at which the belt may be operated without failure.The variation in effective diameter which may be obtained in any singlepulley construction is also determined by the maximum width of the belt,which may be used without failure of the belt due to lateral buckling.For

if too wide a belt is used the belt will buckle" due to the lateralpressure of the pulley faces on the belt sides. It is thus obvious thatthe variation in speed, which may be obtained by means of an adjustablepulley structure is limited, and that it is never possible to adjust thespeed ii to zero or to reverse the direction of rotation by a merevariation in the relative diameters of the driving and driven pulleys.

It is one of the objects of this invention to make. it possible to varythe speed of a driven lit shaft to zero, in a continuous manner, andduring continuous operation of the source of power.

. The possibility of providing such a wide variation in speed rendersthe application of such systems practicable for all kinds of loads. For15 example, the speed of a printing press drive must be capable ofvarying from a high speed down to a very low speed, corresponding to themakeup speed and operating speed. Another ap= plication for such avariable speed system is of hi) fered by machines having a large inertiaand which it is desirable to bring up to speed gradually. The presentinvention makes it possible to start the driving motor, with the speedof the load driving shaft adjusted to zero, after which 25 the speed ofthe load driving shaft may be grad= ually adjusted to bring the drivenmachine to the required speed. The invention finds further ap plicationin driving compressors for refrigerating systems, or fans forventilating systems, in which 550 the demand placed on the drivenmachine is variable. In driving machines of this type it has been commonpractice to operate the machine intermittently in accordance with thevarying de= mend placed on the driven machine. That type 35 of operationrequires a frequent starting and stopping of the driving motor, whichrequires mo== tors of large horsepower and rugged and expensive controlequipment; By the aid of the presentinvention, the speed of the loaddriving shaft may be adjusted to provide the speed required by thedemand placed on the,,driven machine, and f if necessary, the speed of te load driving shaft, may be adjusted to standstill, thereby obviatingthe necessityof stopping the operation of the as driving motor.

It is accordingly, another object of this invention to provide avariable speed drive of this character in which the variation in speedis obtained by the aid of a variable diameter 'pulley 50 structure.

The wide variation in speed is secured by the provision of adiiferential ear mechanism, having two actuating membe .and a drivenmember, which is in driving relation to a load driv- 55 ing shaft. Thespeed of the load driving shaft is adjusted by varying the relativespeeds at which the actuating members are operated. In such adifferential gear mechanism the power delivered to the load drivingshaft is the difierence between the power delivered to one of theactuating members and the power removed from the other actuating member.When the speed of operation of the actuating members is made such thatthe power delivered to one of the actuating members is equal to thepower removed from the other actuating member, the load driving shaft isbrought to a standstill. One of the actuatingmembers may be driven at aconstant speed, and the other at a variable speed, such as that obtainedby a variable diameter pulley drive. However, a greater variation in thespeed of the load driving shaft may be obtained, and 'themaximum torqueon the differential gear mech-' anism reduced, by driving both of theactuating members at variable speeds.

It is accordingly still another object of this invention to provide anadjustable speed differential drive, in which means are provided foradjusting the speeds of both of the actuating members of thedifferential gear mechanism.

The variable speed drive, employed for varying the relative speeds ofthe actuating members of the different gear mechanism, may have two adustable diameter pulley structures; or it "may include oneadjustable-pulley structure and one pulley having a fixed effectivediameter. when two oi the other pulley structure.

adjustment of the two pulleys must be so inter i is of constant length.The use of such interlock-- adjustable pulley structures are employed,the pulleys are arranged to be oppositely adjustable;

that is, an increase in the eflective diameter of one of the pulleystructures isaccompanied'by a compensating decrease in the effectivediameter looked that they are simultaneously adjusted to the diametersrequired by the driving belt, which ing means requires that the drivingand'driven pulleys be adjacently located with respect to each other,-and that they be accessible tov the interlocking means. The adjustment.of both pulleys also requires that the two pulleys be adjusted atvariable relative rates dependent on the particular values of theeflective pulley di-r meters and of the belt lengths.

- Thereare many variable I power applications, for which it is notonvenient to adjacently locate the driving and driven pulleys.

This is particularly true when thejdriving pulley.

structure is directly mounted on the shaft or the driving motor. Formany occasions arise, when there is not suflicient space available toprovide'a common support for both the difi'erential gear mechanism,driven by the driven pulley structure, and the driving electricmotor-and,

driving pulley structure.

. in this device means are provided for adjusting The device to bedescrlbedhereinafter is of' particular utility in such instances.However, it may also be employed with equal succesawhen the two pulleystructures are adjacently located.

In the form of the variable speed drive employed the eflective; diameterof only one or thepulley structures.- The other pulley structure may beof fixed diameter and of the type commonly employed in- V belt drive. I

relatively adjustable 1a compensating aivaaes In that "case the In thisconstruction the for driving. both of the actuating members ofstructures is mounted on the shaft of a driving electric motor. Thesepulley structures are connected by a pair of belts with a second pair ofpulley structures which are respectively in driving relation to the twoactuating-'members of the,

diflerential gear mechanism. To provide-means for adjusting the centerdistance in accordance with the requirements of the adjustable diameterpulley, the electric motor, together with the In order to provide acommon source of power the'difierential gear mechanism, a pair of pulleypulley structures driven thereby, are adjustably mounted on a movablebase.

' actuating member of the differentiaifgear mechanism It is stillanother object of this invention to provide. a variable .speeddifferential drive, in which both of the actuating members of thedifferential gear mechanism may be driven in the same. direction, toreduce the load. imposed on the gears and to increase the power capacityof the drive I invention possesses many other advantages, and hasotherobjects which may be made more easily apparent from a considerationof.

several embodiments of the invention. For this purposethere are shown afew forms, in the drawings acompanying and forming a part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be under stoodthat this detailed descriptionis not to be taken in 'a limiting sense,since the scope of the invention is best defined by the appended claims,

Referring to the drawings:

Figure 1' isa plan view, partly in section, of

a variable speeddifierential drive, embodying the,

invention: Y Figure 2 is a side elevation,.taken from the front ofFigure-l;

Figure 3 is a vertical sectional v1ew,.- taken along the plane'3-3 ofFigure 1;

Figure 4 is a vertical sectional view, taken along 1 the plane 44 of Fie 1;-'

5 is a plan view, partly in section, of

another 'form of variable speed differential drive, embodyingtheinvention;

Figure 6 is a vertical sectional wen -taken. along the plane-Hofiigure5;

Figure 7 is a plan view, partly in section, of

another form of variable speed differential drive,

embodying the invention; and

Figure 8 is a side elevation, t ken from the front of Figure 7.

.Reterring more. particularly to the form of the invention disclosed inFigures 1' to 4, inclusive,

the variable speed drive includes the driving elec-. tric motor I, whichbymeans of the pulley struc-;

turesz and 3 and the belts 4 and 5 drives thepul- Y ley structures 6 andl, which are in driving rela-- tion to the diiierential gear mechanism8. 1 The pulley 6 is indriving relation to the shaft 8,,

which is rotatably supported by the bearing bushing 34, and whichthedriving pinion it secured thereto, by means of the-lock nuts 36'.

The pinion it is in relation to the gears and. I2, whichare secured tothe shafts l3 and I4. The shafts l3 and I4 are carried by the rotatablysupported spider l5. One end of each of the shafts is directly supportedon the spider by the bearings l6 and H, and the other ends of the shaftsare rotatably supported by the bearing supporting plates 18 and is,which are removably secured to the flange 38, Figure 4. To provide meanswhereby the bearing supporting plates may be accurately located withrespect to thespider, the flange 0 member 23; The pulley "I is formeddirectly on the cover member 24, which is removably secured to thehousing 23 by the bolts 40. I

It is obvious from the construction that when the motor I is inoperation, the gears l0 and 22.will be driven respectively by thepulleys 6 and 'l. The gear 22 is made with a greater diameter than thegear l0, thereby causing the gears 20 and 21 to have a smaller diameterthan the gears H and i2. It is obvious from the construction 0 that, ifthe gears l0 and 22 are driven in the same direction at the same speed,the engagement of the gears 20 and 2| with gear 22, and of gears II andI2 with gear ID, will lock the spider l5 to the gears HI and 22, causingthe spider to rotate at the same speed, at which the gears l0. and 22are rotated. However, when the gear I0 is rotated 'at a greater speedthan-the gear 22, 'the shafts l3 and 14 together with the gears securedthereto will rotate about their axes, causingthe spider l5 to bedrivenat a speed less than the I speed of rotation of 'gear 22. Thus if thespeed of rotation of the gear I0 is increased and that of the gear 22 isdecreased, the speed of rotation of the shafts l3 and I4 will beincreased until a condition is arrived at, when the spider I5 isbroughtto a standstill.

It is thus obvious that if a load driving shaft is attached to thespider l5, the speed of rotation of the load driving shaft may beadjusted by varying the relative speeds at which the gears l0 and 22 aredriven. In the present instance the spider l5 has-the loaddriving shaftsecured thereto, which projects to the exterior of the housing 23. Theloaddriving shaft 25 is rotatably supported coaxial with thegears l0 and22 and the shaft 9 by the bearing bushing 35, which is secured to thecover member 24.

To provide means for pivotally supporting the casing 23; the main bodyof the casing 23 and the cover member24 are respectively provided withthe stub shafts 26 and 21, which arepivotally supported within bearingsheld by the upright arms 28 and 29'. To provide means wherebythe housing23 may be quickly removed from its support,-when it is desired to changethe driving belt, the bearings on the upright arms are formed in twoparts. Thus the stub shaft 2'! is rotatably supported by the splitbearingubushin'gs 30 and 3 I, which are respectively held by the uprightarm 29 and the bearing cap 32. It is obvious from the construction'that,the housing 23 may be quickly removed from its supports, upon theremoval of the screws 33, holding the bearing caps to the upright arms28-and 29.

The removable cover member 24 provides means whereby the gears of thediflerential transmissionmay be quickly removed from the enclosinghousing 23. The spider I5 is supported having an internal diametergreater than the diameter of ,the gear 22. Thus when the bolts 40,

holding the cover plate 24 to the body member 23,

V have been removed, the cover plate, together with the spider l5 andthe gears supported thereby,

may be removed as a unit from the transmission housing. When the spiderI5 has been removed from the transmission housing, the shafts l3 and [4,together with the gears supported thereby,

may be removed from the spider, upon the removal of the bearingsupporting plates l8 and IS.

The manner in which the speed of the load driving shaft 25 is adjustedby means of a variation in the relative speedsat which the pulleys 6 andJ are driven, has been disclosed. Consider now the means provided forvarying the relative speeds of rotation of the pulleys 6 and I. Thepulley 5 is driven by the belt 4 and the pulley 2, which is mountedonthe projecting end 43 of. the motor shaft. The pulley 2 is of fixeddiameter, and may be suitably secured to the motor shaft by the setscrew 44 and the key 45. Thepulley a is an, adjustable diameter pulleyand includes the pulley sections 46 and 41, which are splined to theshaft 9 by the key 48. The pulley section- 46 is axially fixed to theshaft 9 by the set screw 45, and the pulley section" is supported foraxialmovement, to provide means for adjusting the effective pulleydiameter. The pulley section N is constantly urged toward the pulleysection46 by the compression spring 50, whichencompasses the hub of thepulley section, and which is held between the collar 5|, secured to theshaft 9, and the shoulder 52 formed on the pulley section.

- To provide means for adjusting'the" effective diameter of the pulleystructure, the driving motor I, together with the pulley 2, is mountedon the-sliding base 53, which in turn is supported by the sub-base 54.The movement of the sliding base 53 is guided by the engagement of thetongue members 55 and 56, formed on the sliding base,

with the grooves 51 and 58, formed on the subbase '54. Suitablemeans areprovided for adjusting'the position of the sliding base 53 with respectto the sub-base. In the present instance the sliding base 53 has thethreaded bushing 59 secured thereto, which threadedly engages the leadscrew'lifl, rotatably. supported on the sub-j base 54. -The lead screw60 is held against axial movement by the 'hand wheel BI and the collarincrease in the center distance between the pule' leys 2 and 5, producedby a rotation of the hand wheel 6|, will result in an increase in thetension of the driving belt 4. An increase in belt tension, in. turn,causes the belt to be urged It is ob-.

radially inward between the opposing faces of the pulley sections 46 and41 to decrease the effective diameter of the pulley structure 6.Conversely,

a decrease in the center distance will result in a decreased belttension, which will permit the the adjustable pulley structure 6 isadjusted, the

belt 4 is moved axially over the inclined face of the pulley section 46.Thus when the center distance between the axes of the pulley structures2 and 6 is increased, to decrease the effective diameter of the pulleystructure 6, the belt 4 is moved axially along the inclined face of thepulley section 46 toward the top of the drawing, as viewed in Figure 1.Thus in order to maintain the belt in alignment, it is necessary to movethe pulley structure 2 in an axial direction simultaneously with thechange in center distance. In the present instance this is accomplishedby forming the grooves 51 and 58 onan angle, such I that when the centerdistance is increased, the motor I, together with the pulley 2, will bemoved toward the top of the figure, as .viewed in Figure 1, to maintainthe belt in alignment.

It is to be noted that the diameter of the adjustable pulley 6 isdecreased,'when the center distance is increased. The driving motor' Ihas a substantially constant speed, thus when the' center distancebetween the pulleys 2 and 6 is I rotation of the gear 22, the fixeddiameter pulley I is driven by the belt 5 and the adjustable diameterpulley structure 3. The adjustable pulley structure 3 includes thepulley sections 64 and 65, which are splined to the extending end 66 ofI the motor shaft by the .key 61. The pulley section 64 is axially fixedto the motor shaft by the set screw 66, and the pulley section issupported by axial movement. The pulley section' 65 is constantly urgedtoward the pulley section 64 by the compression spring 69, which is heldthe pulley structures 3 and I will result in a corresponding'decrease inthe effective diameter of the adjustable pulley structure 3. Whenthe-effective diameter of the adjustable pulley strucviewed in Figure 1.withthe pulley section 64, is moved toward the ture 3 is decreased, thebelt 5 is moved along the inclined face of. the pulley section 64 in anaxial direction toward the bottom of the drawing, as Thus if the motortogether top of the-figure, as viewed in Figure 1, when the centerdistance is increased, the beltwill be maintained in alignment. Thisobviously is themo .tion, which isprovided by the angular guide, formedby the tongue members 55 and 56 and the grooves 5'! and. 58, formed onthe sub -base' 5 '4-. The adjustable diameter pulley 3 is mounted on themotor shaft and thus has-a substantially constant speed. the centerdistance between the pulleys 3 and I is increased, the diameter of thedriving pulley 3 is decreased, Thus an increase in the center distanceresults in a decrease in the speed of rotation of the pulley 1 and ofthe gear 22 driven thereby.

It is thus obvious that when the sliding base 53 is adjusted to increasethe center distance between the driving and driven pulleys, the speed ofrotation of the pulley 6 will be increased and the speed of rotation ofthe pulley 1 will be decreased. Thus an increasing adjustment of thecenter distance will produce a decrease in the speed of the load drivingshaft 25. It isthus obvious that, by means of the construction provided,the speed of the load driving shaft may be adjusted in a continuousmanner, during the operation of the drive in a power transmittingdistance between the axis of the motor' shaft and the axis of the loaddriving shaft, to gradually bring the driven machine up to the requiredspeed.

Itis to be noted that in the high speed position, which is illustratedby Figure 1,. pulleys 6 and fl and the load driving shaft 25 all rotatein the same direction. Thus the speed of rotation of the gears mountedon the shafts I 3 and I 4 is reduced to a minimum, thereby greatlyincreasing the life of the gears'and the power capacity of the entirevariable speed transmission.

Figures 5 and 6 illustrate another form of dif- '.feren'tia.l gearmechanism, which may be employed with the adjustable pulleys and drivingin the construction of Figure 1, the-housing I3 I is rotatablysupported'on the upright arms 28 and 29, by means of the stub shaft I5,formed on the member 14, and the stub shaft 21 formed s on the covermember 24. In this form the differential gear mechanism is actuated bythe pinion 16, mounted on the shaft 9, and by the ring gear 11, which ispressed into the casing member 14 and suitably locked in place, as bymeans of the split ring 16. The pinion 'l6drives the idler gears 19 and86, which are rotatably supported on the stub shafts 8| and 82, securedto the spider member 83. The idler gears 19 and 80. respectively engagethe gears 84 and 85,

-mounted on the stub shafts 86 and6'l, secured to the spider member 83..The gears 84 and 65, in turn, engage the ring gear 11. The spider 83hasthe load driving shaft. 88 secured thereto,v -Wl'110h is rotatablysupported on the cover member 24 by the bearing bushing 35.

It is obvious from the construction that, if the pinion l6 and thering'gear II are both driven direction of rotation of the pinion it. Theengagement of the gears 85 an S5 with the ring gear ll then causes thespider 83 to be driven, in the direction of rotation of the ring gearll, a speed less than that of the ring gear. It is obvious that, if thespeed of rotation of the pinion it is increased, and the speed ofrotation of the ring gear ill decreased, a condition will arise atwhich, the spider 33' will be brought to a standstill. 19 As in theconstruction of Figure 1, the adjustable diameter pulley ii is driven bythe fixed diameter pulley 2 and the fixed diameter pulley i is driven bythe adjustable diameter pulley 3. Thus in the position illustrated by Fiure 5, the 15 pulley t is being rotated at its minimum speed, and thepulley l at its maximum speed. This position of the pulley structuresthus corresponds to a maximum speed of rotation of the load drivingshaft For when the center distance is increased, to decrease theefiective diameters of the pulley structures, the speed of rotation ofthe pinion it will be increased and the speed of rotation of the ringgear it will be decreased, to decrease the speed of rotation of the loaddriving shaft As in the construction of Figure l, the differential gearhousing it) may be quickly removed from its support, by removing thebearing caps n holding the stub shafts l5 and 2'? to the upright arms 28and 29. The spider '53, together with the gears supported thereby, maythen be removed from the gear housing, by removing the bolts ill,holding the cover member 25 to the casing member ii Gears iii, SE 3 3and 35 are in turn removably secured to the spider -83 by the stubshafts ill, 82, 8t and Si. As illustrated by Figure 5, each of thestub-shafts is secured to the spider by means of a nut which engages athreaded end of the n stub sl'iaft. Thus the stub shaft til is providedwith the threaded end 99, which together with the nut provides means forholding the stub shaft to the spider. Each of the gears is rotatablysupported on its shaft by means or a bearing bushing, which is heldbetween the head of the st shaft and the face of the spider. the isprovided with a bearing bushing ssed into the gear, and which is held ofthe stub shaft and the 1 e spider it is obvious from the constructioneach of the gears may be re moved from as supporting spider by removingthe ing the threaded end or he stub shaft.

it is to be noted that, as in the constructionof Figure i, when thespeed of rotation of the load driving shaft is increased, the-speed ofrotation of the gears, supported on the spider, is decreased. Thus bymeans of the construction to provided, the life of the transmissiongears and the power capacity of the diflerential gear mechanism areincreased to a maximum.

Figures '1 and 8 illustrate another form of variable speed differentialdrive, embodying the in- 65 vention. In this form the difierential gearmechanism 93 is enclosed within the housing 53d, formed -by the casingmember 535 and-the cover member The cover member 9b is removably securedto the casing member 95 by the bolts 9i, and 7 the entire differentialgear mechanism is sup ported by the feet 98, formed on the casing memberse. The difierential gear mechanism is actuated by the driving pinion b9and by the spider illli, having the gears till and our rotatablysupported thereon. The gears iglli and iii? engage shaft lh'l. The shaftltd has the fixed diameter pulley lit mounted thereon, which is suitablysecured to the shaft by the set screw iii and the key a a2. The shaftnew is driven by the pulley Me", which is suitably keyed to the shaft,and held against axial movement by the set screw lit. Thus the pulleylid is in driving relation to the pinion 99 and the pulley M3 is indriving relation to the spider ltd.

If the pulleys lit and i it are driven in the same direction at the samespeed, the gears Hut and it will be locked against rotation. Theengagement of the gears till and W2 with the ring gear tilt will causethe ring gear to be rotated with the pulleys lit and M3 and at the samespeed. Thus for this condition, the load driving shaft ltd will bedriven at the speed of rotation of the pulleys Md and lit. If the speedof the pulley Mills maintained constant, and the'speed of rotation ofthe pulley lid is increased, so that the pinion iii! is rotated at agreater speed than the spider ltd, the gears Mill and M32 will berotated about their axes in a direction opposite to the rotation of thepinion It is thus obvious that the ring gear ltd will then be driven ata speed less than the speed of rotation of the spider lull. If the speedof rotation of-the pinion 99 is further increased, a condition willarise when, the'gears Hill an M32 are rotated at a sufilciently to highspeed to bring the ring gear m3 to a standstill. A further increase inthe speed of the pinion till will then result in a reversal in thedirection of rotation of the load driving shaft NM.

The pulley H3 is driven by the belt M5 and the fixed diameter pulleyHi6, mounted on the shaft Oil of the driving electric motor lid. T"nepulley lid is driven by the belt ill) and by the adjustable diameterpulley structure it'd. The adjustable diameter pulley ltd includ'e's'thepulley sections ii-li and 3252, which are keyed to the motor shaft bythe key 523 and which are supported for axial movement. The pulleysection lift is urged into driving relation with the belt by the springi2 3, which isheld between the pulley lid and the reverse side of thepulley section I122. The pulley section it'll is urged into drivingrelation with the belt by the spring [125, which is held between thecollar i526, secured tothe motor shaft, and a shoulder formed-on thepulley section.

To provide means for adjusting the effective diameter of the adjustablepulley structure l2ii, thedriving electric motor M8 is mounted-0n thesliding motor base iii, which, in turn, is sup= ported on the sub haseltd; Suitable means are provided for adiustingthe position of thesliding motor base to vary the center distance between the driving anddriven pulleys of the variable speed drive. In the present instance, theadjust ment of the center distance is efiected by the rotation of thelead screw 539, which threadedly engages the threaded bushing H29,secured to the sl ding base 521. The lead screw is rotatably resupported on the sub-base I 28 and is provided with the manipulatinghand wheel I3i.

center distance, the belt "9 will urge the pulley sections I2I and I22apart, to decrease the effective diameter of the pulley structure I20.Conversely, a decrease in the center distance will result in an increasein the eifective diameter of the pulley structure. In the presentinstance, both pulley sections of the adjustable pulley structure areaxially adjusted. Thus there is no tendency to throw the driving beltout of alignment, when the diameter of the pulley structure is adjusted.The grooves I32 and I33, formed on the subbase for guiding the motion ofthe sliding base I21, are accordingly formed so that they move thesupported motor -I I8 in a direction parallel to the length of the beltH9.

The pulleys H3 and H0 have a fixed eflective diameter. It is accordinglynecessary to provide means for taking up the belt, slack, when thecenter'distance between the pulleys is adjusted; In-the present instancethe idlerpulley I34 is provided, which is rotatably supported on the armI35, pivotally supported on the sub-base I 28. The pulley I34 isconstantly urged into engagement with the back of the driving belt 5 bythe tension spring I36, which is anchored to the subbase 128 andfastenedto the arm I35. It is obvious from the construction that, the spring I36constantly-urges the arm I in an upward direction to hold the idlerpulley I34 against the belt 5.

It is obvious from the construction that, when the center distancebetween the driving and driven pulleys is increased, the diameter of'the adjustable pulley structure I20 will be decreased, therebydecreasing the speed of rotation of the pulley 0. v As has beenpreviously set forth, a decrease in the speed of rotation of the pulleyI I 0 results in an increase in the speed of rotation of the loaddriving shaft I04. Thus when the hand wheel I3I is rotated. to increasethe, center 'distance, the speed of the load driving shaft I04 will"mechanism having two actuating members and a be increased, andconversely, a decrease in the center distance will result in a decreasedspeed ofrotation' of theload driving shaft. It is to be noted that ineach of the forms disclosed the speed of rotation of the gear members isdecreased, when the speed of the load driving shaft isiincreased. Thusunder normal conditions of-operatiomthe gears of the differential gearmechanism operate at a .very slow speed. By means of this constructionthe life and power capacity of the entire variable speed transmission isincreased.

1 claim:

1. In a variable speeddrive, a planetary gear mechanism having twoactuating members and a driven member, a load driving means engagedbythe driven member of said planetary gear mech anism, a pair of pulleystructures in respective driving relationtoeach of said actuating mem-'bers, an electric motor having a shaft, a pair of pulley structuresmounted on said motor shaft, 1:. pairv ofbelts, for transmitting powerbetween the pulley structures mounted on said motor shaft and the pulleystructures in driving relation to said actuating members, one of saidpulley structures mounted on said motor shaft having a fixed diameterand the other of said pulley structures having an adjustable effectivediameter and in cluding a pairrof pulley sections with opposed mentvariable efiective pulley diameters, means for adjustably mounting said.motor to vary the center distance between the axis of said adjustablepulley structure and the axis of the pulley structure in drivingrelation thereto, and means for adjusting the eifectlve diameter of saidadjustable pulley structure in accordance with the adjustment of saidcenter distance, whereby the speed of one of said actuating. members maybe altered with respect to the speed of the other of saidactuating'members.

2. Ina variable speed drive,-a planetary gear mechanism having twoactuating members and a driven member, said actuating members and saiddriven member being relatively rotatable above a common axis, a loaddriving means engaged by the driven member of said planetary gearmechanism, a pair of pulley structures co-.

driving relation to said actuating members, one I of said pulleystructures mounted on said motor shaft having a fixed diameter and theother of said pulley structures having an adjustable effective diameterand including a pair of pulley sections with opposed inclined faces,forming by relative axial adjustment variable efiective pulleydiameters, means for adjustably mounting said' motor to vary the centerdistance between the axis of said motor shaft and the axis of saiddifferential gear mechanism, and means for adjusting the eifectivediameter of said adjustable pulley structure in accordance with theadjustment of said center distance, whereby the speed of one of saidactuating members may be altered with respect to the speed of the otherof said actuating members.

3. In a variable speed drive, a planetary gear driven member, saidactuating members and said driven member being relatively rotatableabout a common axis, a load driving means engaged by saiddriven-member,- a pair of pulley structures mounted coaxial with-saidplanetary gear mechanism'and in respective driving relation to each ofsaid actuating members, one of said pulley structures having aflxeddiameter and the other of said pulley structures having an adjustableeffective diameter, an electric motor having a shaft,

a pair of pulley structures mounted on said motor shaft, one of saidpulley structures mounted on said motor shaft having anadjustable'eifective diameter, and a pair of belts" for transmittingpower between the pulley structures mounted on said motor shaft and thepulley structures mounted coaxial with the diilerential gear mecha-.whereby a simultaneous adjustment of the effective diameters of saidadjustable pulley structures results in a corresponding adjustment ofthe speed of both of said actuating members, the adjustment in the ratioof transmission to inclined faces, forming by relative axial adjustadriven member, a load driving means engaged by said driven member, apair of pulley structures in respective driving relation to each of saidactuating members, one of said pulley structures having an adjustableefiectivepulley diameter, and the other of said pulley structures havinga fixed effective diameter, a driving shaft, a pair of pulley structuresmounted on said driving shaft, one of said pulley structures mounted onsaid driving shaft having an adjustable effective diameter and the otherpulley structure having a fixed effective diameter, a pair of belts fortransmitting power between the pulley structures mounted on said drivingshaft and the' pulley structures in driving relation to said actuatingmembers, each of said belts being in driving relation with one of saidadjustable pulley structures and one of said fixed diameter pulleystructures, means for adjustably mounting said driving shaft to vary thecenter distance between the axes of the pulley structures in drivingrelation with each of said belts, and means for" adjusting the effectivediameter of each of said adjustable pulley structures in accordance withthe adjustment of said center distance, whereby the operating speeds ofsaid actuating members are adjusted in opposite directions to adjust thespeed of said lead driving means.

5. In a variable speed drive, a planetary gear mechanism having twoactuating members and a driven member, a load driving means engaged bysaid driven member, a pair of pulley structures in respective drivingrelation to each of said actuating members, one of said pulleystructures having adjustable eifective diameter, and the other of saidpulley structures having a fixed effective diameter, an electric motorhaving a shaft, a pair of pulley structures mounted on said motor shaft,one of said pulley structures mounted on said motor shaft having anadjustable eiiective diamter and the other pulley structure having afixed ective diameter, a pair of belts for transmitting power betweenthe pulley structures-mounted on said motor shaft and the pulleystructures in driving relation to said actuating members, each or" saidbelts bein in driving relation with one of se adjustable pulleystructures one of use diameter pulley s ructures, means for -djustablymounting said electric motor to vary the center distance between theaxes of the pulley s uctures in driving relation with each of saidbelts, and means i'or adjusting the effective dieters of said adjustablepulley structures, the speed of operation oi one of said a i members isincreased and the speed of cool ation of the other of said actuatingmembers is decreased to adjust the speed of saidload means. i v 6. In avariable speed drive, a planetary gear mechanism having two actuatingmembers and a driven member, a load driving means engaged by said drivenmember, a pair of pulley structures in respective driving relation toeach of said actu ating members, one of said pulley structures have ingan adjustable effective diameter and the other said pulley structureshaving a fixed effective diameter, a driving shaft, a pair of pulleystructures mounted on said driving shaft, one or said pulley structuresmounted on said driving shaft having an adjustable effective diameterand the other pulley structure having a fixed efiective diameter, a pairof belts for transmitting power between the pulley structures mounted onsaid driving shaft and the pulley structures in driving relation to saidactuating members, each of said belts being in driving relation with oneof said adjustable pulley structures and one of said fixed diameterpulley structures, each of said adjustable pulley structures includingan axially fixed pulley section and a pulley section axially adjustablewith respect to the fixed pulley section, said pulley sections havingopposed inclined faces, whereby an axial adjustment of the axiallyadjustable pulley section results in a corresponding variation in theefiectivediameter of theadjustable pulley structure and in an axialmovement of the driving belt with-respect to the fixed pulley section,means for adjustably mounting said driving shaft for movement in a.direction to adjust the center distance between themes of the pulleystructures in driving relation with each of said belts, as well as in adirection to maintain the belts in substantial alignment.

.7. In a variable speed drive, a planetary gear mechanism having twoactuating members and a driven member, a load driving means engaged bythe driven member of said planetary gear mechanism, a pair of variablespeed power transmis sions in respective driving relation to each. ofsaid actuating members, to drive both of them in the same direction,each of said variable speed transmissions including an adjustablediameter pulley structure, a fixed diameter pulley structure and a beltfor transmitting power between said pulley structures, a driving shaftin driving relation to said variable speed transmissions, and

' means for adjusting the effective diameters of each of said adjustablepulley structures to increase the operating speed of one of saidactuating for rotation about said common axis, a load driving shaftrotatably supported coaxially with said casing and connected to saiddriven member,

a shaft rotatably supported coaxially with said planetary gear mechanismand engaging one of said actuating members, means for securingthe otheroi said actuating members to said casing to rotate therewith, a pair oipower transmission means in respective driving relation to said casingand to said shaf to drive them in the same direction, and'means foradjusting the s eed ratio 01" both of said power transmission means.

9. In a variable speed drive, a planetary gear mechanism having twoactuating members and a driven member, said actuating members and saiddriven member being relatively rotatable about a common axis, a casingenclosing and providing means for supporting said planetary gearmechanism, means for rotatably supporting said casing for rotation aboutsaid common axis, means for securing one of said actuating membars tosaid casing, a load driving shaft connected to said driven member androtatably supported coaxially with said casing, a pair of pulleystructures supported coaxially with said planetary gear mechanism, oneof said pulley structuresbeing connected to said casing and the other ofsaid pulley structures being in driving relation td the other of saidactuating members, a driving shaft, a pair of pulley structures mountedon said driving shaft, agpair of belts in driving relation to saidpulley structures mounted on said driving shaft and to said pulleystructures coaxial with the planetary gear mechanism, said structurescoaxial with the planetary gear mechanism being rotated in the samedirection, one of being .in coaxial driving relation to one of theactuating rfiembers, whereby the relative speeds at winch said actuatingmembers are operated may be varied, said driving pulley structures thepulley structures in driving relation with bemg mounted on the drivingshaft, an electric each of said belts having an adjustable effectivediameter, and means to adjust simultaneously the etfectivediameters ofsaid adjustable pulley structures, the pulley structures being such thatthe adjustment in the ratio of drive ,between one pair of pulleystructures is difierent from the simultaneous adjustment in the ratio ofdrive between the other pair of pulley structures.

10; In a variable speed drive, a planetary gear mechanism'having twoactuating members and a load driving member, a pair of power transmitofsaid center distance, the other power transmitting means including apair of pulley structures as well as a belt connecting the pulleystructures, the pulley structures being such that as the center distanceis varied, the increment or decrement in the speed of one actuatingmember is different from the increment or decrement in the speed of theother actuating member.

11. In a variable speed drive, a device for compounding motion haivingtwo actuating members and a driven member, a load driving means engagedby the driven member, a pair of power transmission means in respectivedriving relation to each of said actuating members, a driving shaft foroperating said pair Jf power transmission means, each of said powertransmission means including a driving pulley structure, a driven pulleystructure and a belt for transmitting power between said pulleystructures, at least one of all said pulley structures including a pairof pulley sections with opposed inclined faces, forming by relativeaxial adjustment variable efiective pulley diameters, said variableeffective diameter pulley being in coaxial driving relation to one of.the actuating members whereby the speed ratio of one of said powertransmission means may be varied with respect to the speed ratio of theother power transmission means, means for adjustably mounting saiddriving shaft to 'vary the distancebetween the axes of said drivingpulley structures and said driven pulley structures, and means foradjusting the effective diameter of said adjustable pulley structure inaccordance with the adjustment of said center distance.

' 12. In a variable speed drive, adevice for compounding motion, havingtwo actuating members and a driven member, a pair of power transmissionmeans in respective driving relation to.each of said actuating members,a drivingshaft for operating said pair of power,transmission means, eachof said power transmission means including a driving pulley structure, adriven pulley structure, and a belt fortransmitting power between saidpulley structures, at least one of all said pulley structures includinga, pairof pulley sec tions with opposed inclined faces, forming byrelative axial adjustment-variable effective pulley diameters, saidvariable eifective pulley motor in driving relation to said shaft, meansfor 4 adjustably mounting said electric motor and said shaft to vary thedistance between the axes of said driving. pulley structures and saiddriven pulley structures, and means to vary the effective diameter ofsaid adjustable pulley structure.

13. In a variable speed drive, a device for compounding motion havingtwo actuating members and a driven member, a load driving means engagedby said driven member, a pair of variable speed power transmissions inrespective driving driving relation to each of said actuating members,each of said variable speed transmissions including an adjustablediameter pulley structure, a fixed diameter pulley structure and a beltfor transmitting power between said pulley structures, said adjustablediameter pulley structures being independent of each other, whereby thebelts may be kept in substantially perfect alinement with theirrespective pulley structures for all adjustments of said adjustablediameter pulley structures, and means for simultaneously adjusting theeifective diameters of said adjustable pulley structures to vary therates of transmission in each of said power transmission means, theadjustment in the rate of transmission to one of said actuating membersbeing diflerent from the simultaneous adjustment in the rate oftransmission to the other of said actuating members.

14. In a variable speed drive, a device for compounding motion havingtwo actuating members and a driven m'ember, aload driving means engagedby said driven member, a pair of variable speed power transmissions inrespective driving relation to each of said actuating members, each ofsaid variable speed transmissions including an adjustable diameterpulley structure, a fixed diameter pulley structure and a belt fortransmitting power between said pulley structures, said adjustablepulley structures being on different shafts, whereby the belts may bekept in substantially perfect alinement with their respective pulleystructures for all adjustments of said adjustable diameter pulleystructures-and means for'simultaneously adjusting the eifectivediameters of said adjustable pulley structures to vary the rates oftransmission in each of said power transmission means, the adjustment inthe rate of transmission to one of said actuating mem-j bers beingdifferent from. the simultaneous adjustment in the rate of transmissionto the other of said actuating members.

15. In a variable speed drive, a device for compounding motion havingtwo actuating members and a load driving member, a pair of powertransmitting means in respective driving relation to each of saidactuating members, a' shaft for operating both'of said powertransmitting means,

16. In'a variable speed drive, a device for compounding motion havingtwo actuating members and a driven member, a load driving means engagedby the driven member, a pair of power transmission meansin respectivedriving .relation to each of the actuating members, for rotating them inthe same direction, a driving shaft for operating said pair of powertransmission means, said pair of power transmission means includingmeans whereby the speed of one of said actuating members may be alteredwith respect to the speed of the other 01' said actuating members inrespome to variations in the center distance petween said shaft and saidactuating 5 DON HEYER.

